package com.hmdp.service.impl;

import cn.hutool.core.bean.BeanUtil;
import com.hmdp.dto.Result;
import com.hmdp.entity.SeckillVoucher;
import com.hmdp.entity.User;
import com.hmdp.entity.VoucherOrder;
import com.hmdp.mapper.VoucherOrderMapper;
import com.hmdp.service.ISeckillVoucherService;
import com.hmdp.service.IVoucherOrderService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.utils.RedisIdWorker;
import com.hmdp.utils.SimpleRedisLock;
import com.hmdp.utils.UserHolder;
import lombok.extern.slf4j.Slf4j;
import org.redisson.api.RLock;
import org.redisson.api.RedissonClient;
import org.springframework.aop.framework.AopContext;
import org.springframework.core.io.ClassPathResource;
import org.springframework.data.redis.connection.stream.*;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import javax.annotation.PostConstruct;
import javax.annotation.Resource;
import java.time.Duration;
import java.time.LocalDateTime;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.concurrent.*;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Slf4j
@Service
public class VoucherOrderServiceImpl extends ServiceImpl<VoucherOrderMapper, VoucherOrder> implements IVoucherOrderService {

    @Resource
    private ISeckillVoucherService seckillVoucherService;
    @Resource
    private RedisIdWorker redisIdWorker;        //获取全局唯一id

    @Resource
    private StringRedisTemplate stringRedisTemplate;

    @Resource
    private RedissonClient redissonClient;

    //静态代码块执行脚本
    private static final DefaultRedisScript<Long> SECKILL_SCRIPT;
    static {
        SECKILL_SCRIPT = new DefaultRedisScript<>();
        SECKILL_SCRIPT.setLocation(new ClassPathResource("seckill.lua"));
        SECKILL_SCRIPT.setResultType(Long.class);
    }
    

    //线程池
    private static final ExecutorService SECKILL_ORDER_EXECUTOR = Executors.newSingleThreadExecutor();
    
    @PostConstruct      //在当前类初始化完毕以后执行
    private void init(){
        SECKILL_ORDER_EXECUTOR.submit(new VoucherOrderHandler());
    }

    private class VoucherOrderHandler implements Runnable{
        String queueName = "stream.orders";
        @Override
        public void run() {
            while (true){
                try {
                    //1. 获取消息队列中的订单信息 XREADGROUP GROUP g1 c1 COUNT 1 BLOCK 2000 STREAMS streams.order >
                    List<MapRecord<String, Object, Object>> list = stringRedisTemplate.opsForStream().read(
                            Consumer.from("g1", "c1"),
                            StreamReadOptions.empty().count(1).block(Duration.ofSeconds(2)),
                            StreamOffset.create(queueName, ReadOffset.lastConsumed())
                    );
                    //2. 判断消息获取是否成功
                    if (list == null || list.isEmpty()){
                        //2.1 如果获取失败，说明没有消息，继续下一次循环
                        continue;
                    }
                    //3. 解析消息中的订单信息
                    MapRecord<String,Object,Object> record = list.get(0);
                    Map<Object, Object> values = record.getValue();
                    VoucherOrder voucherOrder = BeanUtil.fillBeanWithMap(values, new VoucherOrder(), true);
                    //3. 如果获取成功，可以下单
                    handleVoucherOrder(voucherOrder);
                    //2. ACK确认  SACK stream.orders g1 id
                    stringRedisTemplate.opsForStream().acknowledge(queueName,"g1",record.getId());
                } catch (Exception e) {
                    log.error("处理订单异常",e);
                    handlePendingList();
                }
            }
        }

        private void handlePendingList() {
            while (true){
                try {
                    //1. 获取pending-list中的订单信息 XREADGROUP GROUP g1 c1 COUNT 1  STREAMS streams.order 0
                    List<MapRecord<String, Object, Object>> list = stringRedisTemplate.opsForStream().read(
                            Consumer.from("g1", "c1"),
                            StreamReadOptions.empty().count(1),
                            StreamOffset.create(queueName, ReadOffset.from("0"))
                    );
                    //2. 判断消息获取是否成功
                    if (list == null || list.isEmpty()){
                        //2.1 如果获取失败，说明pending-list没有消息，结束循环
                        break;
                    }
                    //3. 解析消息中的订单信息
                    MapRecord<String,Object,Object> record = list.get(0);
                    Map<Object, Object> values = record.getValue();
                    VoucherOrder voucherOrder = BeanUtil.fillBeanWithMap(values, new VoucherOrder(), true);
                    //3. 如果获取成功，可以下单
                    handleVoucherOrder(voucherOrder);
                    //2. ACK确认  SACK stream.orders g1 id
                    stringRedisTemplate.opsForStream().acknowledge(queueName,"g1",record.getId());
                } catch (Exception e) {
                    log.error("处理pending-list订单异常",e);
                    try {
                        Thread.sleep(20);
                    } catch (InterruptedException interruptedException) {
                        interruptedException.printStackTrace();
                    }
                }
            }
        }
    }


    /*//阻塞队列
    private BlockingQueue<VoucherOrder> orderTasks = new ArrayBlockingQueue<>(1024 * 1024);
    //线程任务
    private class VoucherOrderHandler implements Runnable{
        @Override
        public void run() {
            while (true){
                try {
                    //1. 获取阻塞队列中的订单信息
                    VoucherOrder voucherOrder = orderTasks.take();
                    //2. 创建订单
                    handleVoucherOrder(voucherOrder);
                } catch (Exception e) {
                    log.error("处理订单异常",e);
                }
            }
        }
    }*/


    //该业务基于线程进行
    private void handleVoucherOrder(VoucherOrder voucherOrder) {
        //1、获取用户
        Long userId = voucherOrder.getUserId();
        //2、创建锁对象
        RLock lock = redissonClient.getLock("lock:order:" + userId);
        //3、获取锁
        boolean isLock = lock.tryLock();
        //4、判断是否获取锁成功
        if (!isLock){
            //获取锁失败，返回错误信息或重试
            log.error("不允许重复下单");
            return;
        }
        try {
            //获取代理对象（事务）
            //IVoucherOrderService proxy = (IVoucherOrderService) AopContext.currentProxy();  //无法获取
            proxy.createVoucherOrder(voucherOrder);
        } finally {
            //释放锁
            lock.unlock();
        }
    }


    //以成员变量方式，放在当前类中，以便于子线程读取时，拿到的是一个现成的代理对象
    private IVoucherOrderService proxy;
    /**
     * 基于redis判断秒杀资格
     * @param voucherId
     * @return
     */
    @Override
    //@Transactional  //设计对两张表进行操作，加上事务回滚，一旦出现问题可以进行事务回滚
    public Result seckillVoucher(Long voucherId) {
        //获取用户
        Long userId = UserHolder.getUser().getId();
        //获取订单id
        long orderId = redisIdWorker.nextId("order");
        //1.执行lua脚本
        Long result = stringRedisTemplate.execute(
                SECKILL_SCRIPT,
                Collections.emptyList(),
                voucherId.toString(), userId.toString(),String.valueOf(orderId)
        );
        //2.判断结果是否为0
        int r = result.intValue();
        if (r != 0){
            //2.1 不为0 ，代表没有购买资格
            return Result.fail(r == 1 ? "库存不足" : "不能重复下单");
        }
        //3、提前获取的代理对象
        proxy = (IVoucherOrderService) AopContext.currentProxy();
        //3. 返回订单id
        return Result.ok(orderId);
    }

    /*@Override
    //@Transactional  //设计对两张表进行操作，加上事务回滚，一旦出现问题可以进行事务回滚
    public Result seckillVoucher(Long voucherId) {
        //获取用户
        Long userId = UserHolder.getUser().getId();
        //1.执行lua脚本
        Long result = stringRedisTemplate.execute(
                SECKILL_SCRIPT,
                Collections.emptyList(),
                voucherId.toString(), userId.toString()
        );
        //2.判断结果是否为0
        int r = result.intValue();
        if (r != 0){
            //2.1 不为0 ，代表没有购买资格
            return Result.fail(r == 1 ? "库存不足" : "不能重复下单");
        }
        //2.2 为0 ， 有购买资格，把下单信息保存到阻塞队列
        //TODO 保存到阻塞队列
        //创建订单
        VoucherOrder voucherOrder = new VoucherOrder();        
        //2.3 订单id
        long orderId = redisIdWorker.nextId("order");
        voucherOrder.setId(orderId);
        //2.4 用户id
        voucherOrder.setUserId(userId);
        //2.5 代金券id
        voucherOrder.setVoucherId(voucherId);
        //2.6 放入阻塞队列
        orderTasks.add(voucherOrder);

        //3、提前获取的代理对象
        proxy = (IVoucherOrderService) AopContext.currentProxy();
        //3. 返回订单id
        return Result.ok(orderId);
    }*/


    @Transactional
    public void createVoucherOrder(VoucherOrder voucherOrder){
        //TODO 6.一人一单
        Long userId = voucherOrder.getUserId();
        //6.1 根据优惠券id和用户id查询订单数
        int count = query().eq("user_id", userId).eq("voucher_id", voucherOrder.getVoucherId()).count();
        //6.2 判断是否存在
        if (count > 0 ){
            //用户已经购买过了
            log.error("用户已经购买过一次！！");
            return;
        }
        //5.扣减库存
        boolean success = seckillVoucherService.update()
                .setSql("stock = stock - 1")        //set stock = stock - 1
                .eq("voucher_id",voucherOrder.getVoucherId()).gt("stock", 0)      //where id = ? and stock > 0
                .update();
        if (!success){
            //扣减失败
            log.error("库存不足！！");
            return;
        }
        //6.创建订单
        save(voucherOrder);
    }



    /**
     * 判断秒杀资格
     * @param voucherId
     * @return
     */
    /*@Override
    //@Transactional  //设计对两张表进行操作，加上事务回滚，一旦出现问题可以进行事务回滚
    public Result seckillVoucher(Long voucherId) {
        //1.查询优惠券
        SeckillVoucher seckillVoucher = seckillVoucherService.getById(voucherId);
        //2.判断秒杀是否开始
        if (seckillVoucher.getBeginTime().isAfter(LocalDateTime.now())) {
            //尚未开始
            return Result.fail("秒杀尚未开始！！");
        }
        //3.判断秒杀是否已经结束
        if (seckillVoucher.getEndTime().isBefore(LocalDateTime.now())) {
            //已经结束
            return Result.fail("秒杀已经结束！！");
        }
        //4.判断库存是否充足
        if (seckillVoucher.getStock() < 1){
            //库存不足
            return Result.fail("库存不足！！");
        }

        //对不同用户加不同锁,锁的是相同用户，
        Long userId = UserHolder.getUser().getId();
        //先获取锁，再进入createVoucherOrder方法完成下单操作
        //synchronized (userId.toString().intern()) {
        //TODO 创建锁对象
        //SimpleRedisLock lock = new SimpleRedisLock("order:" + userId, stringRedisTemplate);
        RLock lock = redissonClient.getLock("lock:order:" + userId);

        //TODO 获取锁
        boolean isLock = lock.tryLock();
        //判断是否获取锁成功
        if (!isLock){
            //获取锁失败，返回错误信息或重试
            return  Result.fail("一个人只允许下一单,不允许重复下单！！！");
        }
        try {
            //获取代理对象（事务）
            IVoucherOrderService proxy = (IVoucherOrderService) AopContext.currentProxy();
            return proxy.createVoucherOrder(voucherId);
        } finally {
            //释放锁
            lock.unlock();
        }
        //}
    }

    @Transactional
    public Result createVoucherOrder(Long voucherId){
        //TODO 6.一人一单
        Long userId = UserHolder.getUser().getId();
            //6.1 根据优惠券id和用户id查询订单数
            int count = query().eq("user_id", userId).eq("voucher_id", voucherId).count();
            //6.2 判断是否存在
            if (count > 0 ){
                //用户已经购买过了
                return Result.fail("用户已经购买过一次了！！");
            }
            //5.扣减库存
            boolean success = seckillVoucherService.update()
                    .setSql("stock = stock - 1")        //set stock = stock - 1
                    .eq("voucher_id",voucherId).gt("stock", 0)      //where id = ? and stock > 0
                    .update();
            if (!success){
                //扣减失败
                return Result.fail("库存不足");
            }
            //6.创建订单
            VoucherOrder voucherOrder = new VoucherOrder();
            //6.1订单id
            long orderId = redisIdWorker.nextId("order");
            voucherOrder.setId(orderId);
            //6.2用户id
            //Long userId = UserHolder.getUser().getId();
            voucherOrder.setUserId(userId);
            //6.3代金券id
            voucherOrder.setVoucherId(voucherId);
            save(voucherOrder);
            //7.返回订单id
            return Result.ok(orderId);
    }*/
}
